Bee-line flow finishing apparatus



March 1970 HISAMINE KOBAYASHI 3,503,153

BEE-LINE FLOW FINISHING APPARATUS Original Filed March 21, 1967 3Sheets-Sheet 1 March 1970 HISAMINE KOBAYASHl 3,50

BEE-LINE FLOW FINISHING APPARATUS Original Filed March 21, 1967 3Sheets-Sheet 2 [lllll March 31, 1970 HISAMINE KOBAYASHI 3,503,153

BEE-LINE FLOW FINISHING APPARATUS Original Filed March 21, 1967 3Sheets-Sheet 3 3,503,153 BEE-LINE FLOW FlNISHlNG APPARATUS HisamineKobayashi, 13, 3-chome, Kikuzono-cho, Showa-ku, Nagoya, Japan Originalapplication Mar. 21, 1967, Ser. No. 624,874. Divided and thisapplication Jan. 22, 1969, Ser. No. 807,152 Claims priority, applicationJapan, June 18, 1966, il/39,505, ll/39,506, 41/139,507 Int. Cl. 1324b31/00 US. Cl. 51-17 6 Claims ABSTRACT OF THE DISCLOSURE A carrier deviceof U-shaped endless belt type composed of a durable wire net is tightlyspanned between a pair of vertical belt wheels and its bottom issupported by a plurality of bearing rollers while each of its side wallsis supported by a plurality of guide rollers except for the ranges ofthe belt wheels. A quantity of abrasives is loaded in the form of aloose layer into the device. One of the belt wheels is driven to rotatethe device and therefore the abrasive layer is moved in one direction inthe horizontal plane. Workpieces are moved one after another incounterflow relation in either or both of the rectilinear portions ofthe traveling abrasive layer. If desired, the workpieces may pushagainst the surface of the rectilinear abrasive portion. Also a layer ofabrasives can be rotated in a vertical plane. A carrier device ofchannelled endless belt type composed of a flexible material is tightlyspanned between a pair of horizontal belt wheels such that the majorpart of its upper rectilinear section formed between the belt wheels isof a substantially U-shaped cross section confined by a plurality ofroller sets such as above described for purpose of surface finishingwhile the remaining section of the devices has a closed cross sectionalprofile by having a plural sets of four rollers disposed on four sidesof the device excepting that the inside rollers are omitted in the rangeof each belt wheel. Further a pair of channelled endless belts can bejuxtaposed into an X-shaped arrangement in the respective verticalplanes and be rotated in the opposite directions. A layer of abrasivesis formed in the ascending upper rectilinear section of each travelingbelt and is transferred from its top end onto the other ascendingrectilinear belt section through a transfer chute. Workpieces aresuccessively passed through one of the rectilinear streams of theabrasive layer from its upper end to its lower end and then transferredto the other rectilinear stream with their orientation remainingunchanged followed by the similar passage through the other stream.Alternatively both rectilinear streams may be utilized for separatefinishing operations. Preferably the speed of the workpieces relative tothe rectilinear abrasive stream ranges from 70 to 500 meters per minuteand the finishing time ranges from 10 seconds to 15 minutes. Therectilinear abrasive stream has a length of from less than 1 to morethan 10 meters. The abrasives may be of either dry or wet type.

This application is a division of my copending application Ser. No.624,874, filed Mar. 21, 1967, now Patent No. 3,449,871.

This invention relates to improvements in the surface finishingtechnique and more particularly to a method of automaticallysurface-finishing workpieces with a rectilinear stream of looseabrasives and an apparatus for carrying out such a method.

The conventional type of surface finishing methods, even though they areof the rotary, vibratory or cen- United States Patent ICC trifugallygyratory barrel type, has been mostly subject to various limitations dueto the conditions for flowing a mass Within a finishing barrel whichconditions depend upon the configuration of the barrel and the type ofdrive therefor involved. By the term mass is meant a mixture ofworkpieces to be finished, abrasives and other materials charged in afinishing barrel. Those limitations lead to other limitations as to theconfiguration and size of the workpieces and to their amount charged ineach barrel also determined by the configuration of the barrel and thetype of drive therefor. Accordingly, the conventional methods havesuccessfully surface finished workpieces relatively small in size andsymmetrical in configuration but they could scarcely succeed with bothlarge-sized long workpieces and the special portions of small-sizedworkpieces. For example, such methods could not surface finish mufflersfor use on autobicycles, bumpers, radiator grilles and decorative strapsfor use in automobiles etc.

It is, accordingly, an object of the invention to provide a new andimproved method of continuously and automatically effecting surfacefinishing of workpieces regardless of their size and configuration andespecially of largesized, long workpieces.

It is another object of the invention to provide a new and improvedmethod of automatically effecting surface finishing of workpieces on thebasis of production line.

Briefly, the invention accomplishes the above cited objects by theprovision of a method of surface finishing workpieces, comprising thesteps of establishing a stream of loose abrasives circulating at leastpartly along a rectilinear path while that portion of the abrasivestream moving along the rectilinear path has a substantially uniformdensity and a predetermined cross sectional profile, and moving theworkpieces, one after another, relative to the rectilinear portion ofthe abrasives stream at a predetermined relative speed in a directionopposite to the direction of the stream while maintaining the workpiecesin surface-finishing engagement with the rectilinear stream portion.

The speed of the workpieces relative to the rectilinear stream portionmay preferably range from to 500 meters per minute.

The invention also contemplates to provide a new and improved apparatusfor carrying out the surface finishing method as above outlined. Theapparatus comprises carrier means of channelled endless belt typecomposed of a flexible durable material, a pair of driving belt wheeland a turning belt wheel for spanning the carrier means in tensionedstate to form a pair of parallel rectilinear sections therebetween, aquantity of abrasives loosely and uniformly distributed in the form of alayer within the carrier means, means for maintaining a substantially U-shaped cross section of at least one of said rectilinear sections ofsaid carrier means, and means for holding and driving the workpieces oneafter another to move at a predetermined relative speed them in adirection opposite to a direction a rectilinear stream portion of theabrasive layer in the U-shaped rectilinear section of the carrier meansdriven by the driving belt wheel while maintaining the workpieces insurface-finishing engagement with the rectilinear stream portion.

In a preferred embodiment, the carrier device composed of a flexibledurable wire net may be spanned in tensioned state between a pair ofvertical belt wheels and has a bottom supported by a plurality ofbearing rollers and both side walls each supported by guide rollersexcept for the range of each belt wheel whereby the cross section of thedevice is maintained a substantially U-shaped. Thus the carrier deviceis rotatable in one direction in a horizontal plane to establish a pairof rectilinear stream portions of an abrasive layer loaded in the devicefor purpose of surface finishing.

In order to surface finish relatively small-sized workpieces, a carrierdevice of channelled endless belt type may be rotated in tensioned statein a vertical plane between a pair of horizontal belt wheels. The majorpart of the upper rectilinear section of the carrier device may besupported a plural sets of rollers such as above described to have asubstantially U-shaped cross. section. In order to prevent a layer ofabrasive formed in the carrier device from falling down from theremaining section of the device, a plural sets of four rollers aredisposed on four sides of the remaining section of the device exceptthat the inside rollers are omitted in the range of each belt wheelwhereby the remaining device section has a cross sectional profilecompletely closed.

For long workpieces, two pairs of carrier devices of channelled endlessbelt type may juxtaposed in tensioned state in the respective verticalplanes to form an X-shaped arrangement by having two pairs of beltwheels engaging the same respectively and rotated in the oppositedirections. The carrier device may advantageously have both side wallseach comprising a plurality of outwardly flared plates alternatingsimilar plates. These outwardly flared plates overlap each other whenthe associated portion of the device is traveling along a rectilinearpath between the associated pair of belt wheels. A layer of abrasive isformed on the ascending upper rectilinear section of each device andtransferred from the upper end thereof onto the ascending upperrectilinear section of the other device through a transfer chute.Workpieces can be successively passed through an ascending streamportion of the abrasive layer on the upper rectilinear section of eachdevice.

The invention as to its organization and its mode of operation as wellas other objects and advantages thereof will become more readilyapparent from the following detailed description taken in conjunctitonwith the accompanying drawings in which:

FIG. 1 is a fragmental plan view of a surface finishing apparatusconstructed in accordance with the principles of the invention withparts removed for purpose of illustration;

FIG. 2 is a fragmental side elevational view of the apparatusillustrated in FIG. 1 with parts removed for purpose of simplificationand with parts broken away for the purpose of illustrating a position ofa workpiece relative to a stream of loose abrasive;

FIG. 3 is a sectional view taken along the line III-III of FIG. 2 andillustrating a roller set for the apparatus;

FIG. 4 is a fragmental side elevational View of a modification of theinvention with parts removed for purpose of simplification and withparts broken away for the purpose of illustrating a position of aworkpiece;

FIG. 5 is a fragmental plan view of the apparatus illustrated in FIG. 4with parts removed for purpose of simplification;

FIG. 6 is a sectional view taken along the line VIVI of FIG. 4 andillustrating a roller set for the apparatus;

FIG. 7 is a view similar to FIG. 6 and illustrating a section takenalong the line VIIVII of FIG. 4;

FIG. 8 is a view similar to FIG. 6 and illustrating a section takenalong the line VIII-VIII of FIG. 4;

FIG. 9 is a fragmental diagrammatic view in side elevation, of anothermodification of the invention with parts removed for purpose ofsimplification and with parts broken away for the purpose ofillustrating a posititon of a workpiece relative to a stream of looseabrasive;

FIG. 10 is a front view of the apparatus illustrated in FIG. 9;

FIG. 11 is a fragmental side elevational view, in enlarged scale of anupper end portion of a carrier device illustrated in FIG. 9

FIG. 12 is a fragmentay sectional view taken along the line XII-XII ofFIG. 11; and

FIG. 13 is a view similar to FIG. 12 but illustrating a modification.

Quite unlike the commonly accepted concept the invention is based uponthe concept that workpieces either push against a surface of arectilinear stream of loose abrasive moving at a predetermined speed inone direction or move through that stream at a predetermined speed inthe opposite direction while they are maintained immersed into thestream.

Referring now to FIGS. 1 to 3 inclusive, there is illustrated a surfacefinishing apparatus of vertical recirculation type constructed inaccordance with the principles of the invention. An arrangementillustrated is of a medium capability and comprises a .pair of verticalbelt wheels 10 and 12 vertically disposed at any desired intervaldetermined for the particular application with one of the belt wheels,for example, the wheel 10 serving as a driving wheel. Between the beltwheels 10 and 12 there is spanned in tensioned state a carrier device ofchannelled endless belt type generally designated by the referencesnumeral 14. The carrier device 14 is substantially of a U-shaped crosssection and composed of any suitable expandable, durable material.Suitable examples of such a material involve a wire net made of astainless wire or the like into an expandable structure with minute meshopenings and such a wire net having bonded on the internal surface asteel wire fabric coated with any suitable plastic.

In order to support and guide the U-shaped carrier device 14 even duringits movement the bottom of the U is supported and guided by a pluralityof bearing rollers 16 substantially coextensive with the same anddisposed at substantially equal intervals throughout the length.Disposed on the outer side wall of the device 14 throughout its lengthis one external guide roller 18 coextensive with the leg of the U in avertical plane passing through the longitudinal axis of each bearingroller 16 while one internal guide roller 20 similar to the roller 18 isdisposed on the internal side wall and directly opposing to each roller18 except for the ranges of each belt wheel 10 or 12. One set of thesethree rollers 16, 18 and 20 is diagrammatically illustrated in FIG. 3.

Thus it will be appreciated that the carrier device 14 is positioned ina space confined by the rollers 16, 18 and 20.

Then a quantity of abrasives 22 is loosely and uniformly loaded in theinterior of the carrier device 14 throughout its length and up to anysuitable level for example, up to approximately two thirds the depth ofthe device to form a layer of abrasive in a closed loop.

It will be appreciated that the abrasives may be of the dry or wet typeor in the form of a paste. If desired, they may contain any suitableliquid such as water, a surface active agent, a glossing material etc.The abrasives may be in the form of a powder or a granule or a cakehaving any suitable shape such as a spherical, a pyramidal, arhombohedral, an ellipsoidal or a cylindrical shape or the like. Theymay have a mean diameter ranging from 0.01 mm. to the order of 50 mm.dependent upon the material, configuration and dimension of workpiecesto be finished.

Under these circumstances, the carrier device: 14 can be rotated in ahorizontal plane by the driving belt wheel 10 driven from an electricmotor (not shown) through a suitable transmission mechanism (not shown).It is now assumed that the belt wheels 10 and 12 are rotated in thedirection of the arrows designated within the respective circles 10 and12 to drive the carrier device 14 in the counterclockwise direction asviewed in FIG. 1 or clockwise direction.

In operation the carrier device 14 effects horizontal movement so thatany cross section thereof travels rectilinearly in the direction of thearrow 24 (see FIG. 1) between the centers of both wheels 10 and 12 whileit is guided by the rollers 16, 18 and 20 and subsequentlysemicircularly in the direction of the arrow 24' around the wheel 10 byvirtue of the latter and rollers 18 and 20 followed by rectilinearmovement in the direction of the arrow 24" between the centers of bothwheels and the subsequent semicircular movement in the direction of thearrow 24 around the driving wheel 12. Therefore it will be appreciatedthat with the carrier device 14 moved, any point on or in the layer ofabrasives 22 loaded in the device eifects horizontal movement includinga pair of rectilinear movement portions between the centers of bothwheels and 12 and a pair of semicircular movement portions around therespective wheels with each of the rectilinear portions merged at eachend into the adjacent semicircular portion. In other words, movement ofthe carrier device 14 causes a stream of abrasive effecting movement ofthe character just described.

The length of the rectilinear movement of the layer of abrasives 22 andaccordingly a distance between the centers of the two belt wheels 10 and12 designated by the reference character L or L may be selected to haveany magnitude dependent upon the size of workpieces to be finished andthe capability of the apparatus to treat the workpieces per each day. Ithas been found that the distance L or L may be varied from a magnitudeas low as less than 1 meter to a magnitude exceeding 10 meters. Also thelayer of abrasives 22 may have any desired width and any desiredthickness in accordance with the particular application.

With the carrier device 14 moved in the counterclockwise direction asviewed in FIG. 1 to establish the stream of abrasives as above.described, any suitable holding and driving means can be utilized tointroduce a workpiece 26 for example from its position 26 illustrated inFIG. 1 into the carrier device 14 adjacent the righthand and lower endportion thereof as shown at the arrow 28 whereupon the workpiece may bepushed against the surface of the lower rectilinear stream portion ofthe abrasives adjacent the end of the rectilinear movement portion.Alternatively the workpiece may be put in the stream. The holding anddriving means are symbolically designated by a small circle within therectangle of the workpiece in FIG. 1. Then the holding and driving meansare operated to move the workpiece 26 in counterfiow relationship on thesurface or in the interior of the stream. One position of the workpiecebeing finished is illustrated at its position 26 in FIGS. 1, 2 and 3.

When the workpiece 26 has reached substantially the beginning or thelefthand end of the lower rectilinear stream portion or when it hassubstantially traveled the distance L, it can be raised from the streamof abrasives and then brought into its position 26" shown in FIG. 1 asthe finished product.

Alternatively if the workpieces 26 is required to be further finishedthen the raised workpiece 26" may be moved along its semicircular path28' around the wheel 10 by the same holding and driving means without itcontacting the semicircular stream portion of the abrasives. Thereafter,when the. workpieces reaches above the end of the upper rectilinearstream portion it will be pushed against or put into that stream portionwhile it ismoved in the direction of the arrow 28 or in counterflowrelationship to be further finished through the use of the same holdingand driving means. At the beginning or the righthand end of saidmovement portion the finished workpieces will be similarly raised fromthe stream and then brought into its position 26 illustrated in FIG. 1as shown at the arrow 28". Thus the workpieces 26 has been completelysurface finished.

In either case it is to be understood that a series of workpieces can besuccessively introduced into the carrier device 14 at any suitableintervals of time to be finished with the rectilinear stream portion orportions of abrasives in the manner as above described.

Thus it will be appreciated that the present apparatus can surfacefinish workpieces on the basis of production line. If a singleproduction line is desired, the workpieces 26 will be successively fedfrom their position 26 to their position 26" in the manner as abovedescribed. Alternatively if workpieces is surface finished on the basisof double production line, the rectilinear portion designated at thearrow 24 of the carrier device 14 may be used to surface finish theworkpieces 26 on the line 28 while at the same time the portion thereofdesignated at the arrow 24" may be used to surface finish workpieces 27on the separate line 28".

From the foregoing it will be apparent that the invention comprises theuse of the rectilinear stream portion of the abrasives along for purposeof surface finishing. Therefore the method and apparatus of theinvention may be called the bee-line flow finishing type.

In practicing the invention the relative speed between the workpiece andthe rectilinear stream portion of the ab.asives is of the mostimportance. In order to perform consistently uniform surface finishingwith a high efficiency and low costs, one must consider an extent towhich the pressure of the loose abrasives in its flowing layer can beapplied to the particular workpiece. It has been found that, forsatisfactory results, the layer of abrasives should have a speed rangingfrom 70 to 300 meters per minute. A speed between and meters per minuteis generally effective for surface finishing workpieces made of iron,steel, stainless steels, non-ferrous metals etc. For extremely stout ortenacious materials or for the purpose of heavy grinding, it has beenespecially found that the speed of the layer of abrasives may range from300 to 500 meters per minute without any damage to workpieces.

It should be understood that the workpieces are required to be put infinishing engagement with the rectilinear stream portion of theabrasives for a period of time sufiicient to be thoroughly surfacefinished with the abrasives in that stream portion. Therefore theworkpieces must relatively travel the length L or L or L L of therectilinear stream portion, as the case may be, for such a period oftime. It has been found that that period of time is preferably in theorder of from 10 seconds to 15 minutes for the speed of the abrasivestream as previously specified. Also it has been found that the relativespeed between the workpieces and the rectilinear stream portion of theabrasives preferably ranges from 70 to 500 meters per minute.

Referring now to FIGS. 4 to 8 inclusive there is illustrated amodification of the invention wherein a stream of abrasives such aspreviously described is established in a vertical plane. An arrangementillustrated may be called the horizontal recirculation type and isespecially suitable for use on a table.

The arrangement comprises a pair of spaced belt wheels 40 and 42disposed in a common horizontal plane and a carrier device of channelledendless belt type generally designated by the reference numeral 44 andspanned in tensioned state between both belt wheels. The carrier device44 is formed of any suitable flexible, tough material such as a flaxfilled urethane rubber or the like and has a quantity of abrasives 52such as the abrasives 22 as previously described.

When a drive (not shown) rotates one of the belt wheels for example thewheel 40 in the direction of the arrow designated within a circle 40 orin the counterclockwise direction as viewed in FIG. 4, any cross sectionof the device 44 travels along a closed loop comprising a rectilinearportion, semicircular portion, another rectilinear portion and anothersemicircular portion consecutive to each other as shown at the arrows54, 54, 54 and 54 respectively as in the arrangement illustrated inFIGS. 1 to 3 inclusive. In this case, however, it is noted that theclosed loop lies in a vertical plane. Therefore it is essential that anyportion of the abrasives 52 within the carrier device 44 should beprevented from falling down from that portionof the device as travelingalong the semicircular portion 54' or 54 or the lower rectilinearportion 54".

To this end, the carrier device 44 made of a flexible,

tough material as above described has a pair of opposed side walls 46longitudinally undulating with valleys 48 of the undulation disposed atsubstantially equal intervals and inwardly foldable. Disposed along themajor part of the upper rectilinear section 54 of the closed loop are aplurality of sets of a bearing roller 60 and side guide rollers 62 and64 (see FIG. 6) at substantially equal intervals to define the U-shapedcross section of the carrier device as traveling along the upperrectilinear section 54. These rollers 60, 62 and 64 may be identical tothe rollers 16, 18 and 20 as previously described in conjunction withFIG. 3 except for the concave contour of the roller 60. The rollers 60of concave contour are effective for centering the carrier device 44. Ifdesired, bearing rollers such as the bearing rollers 16 may be used.

Both a transitional region from the upper rectilinear section 54 to theadjacent semicircular portion 54' or 54" of the closed loop and eachadjacent portion of the semicircular portion are provided with aplurality of sets of four rollers 60', 62, 64' and 66 as shown in FIG. 7disposed at substantially equal intervals. The bearing roller 60 isidentical to the bearing roller 60 and two opposed side guide rollers62' and 64 are shorter than the side guide rollers 62 and 64 andinclined toward each other with the rider roller 66 of concave contourdisposed above the side rollers. As the side guide rollers 62 and 64'are near to the belt wheel 40 or 42 they are more inclined toward eachother and correspondingly the rider rollers 66 may be progressivelyshorter. The roller sets 62'66 are in rolling engagement with theadjacent portions of the carrier device 44 whereby they cooperate witheach other to render the upper opening of the U progressively narrowerin one of the transitional ranges until the opening is completely closedwith both legs of the U somewhat overlap each other as shown in FIG. 8.In the other transitional range they serve progressively to open theupper opening of the U until it is completely opened at the entrance ofthe rectilinear device section.

In order to maintain the closed sectional profile of the carrier device44 on the remaining portion of the closed loop or in the course of thereturn path, a plurality of sets of four rollers 60", 62", 64" and 66"as shown in FIG. 8 are disposed at substantially equal intervals and inrolling engagement with the adjacent portions of the device except forthe semicircular portion thereof. The roller set 6066" are substantiallysimilar to that shown in FIG.'7 excepting that the side guide rollers 62and 64 are substantially parallel to each other and that the rollers 60and 66 are the lower and upper rollers acting as a pressing and abearing roller respectively.

For the semicircular portion 54' or 54" the roller sets are identical tothe roller set 60"-64" except for the side rollers 64" being omitted andinstead replaced by the belt wheel 40 and 42.

With the arrangement of the roller sets as above described it will beappreciated that any cross section of the carrier device 44 ismaintained U-shaped on the major part of the upper rectilinear portion54, and as it approaches the belt wheel 42 its upper opening becomesprogressively narrower until the opening is completely closed.Thereafter the cross section of the carrier device 44 travels along thereturn path 54-54"-54'" while it maintained closed and as it moves awayfrom the belt wheel 40 it is progressively open until it assume the U-shape at the beginning of the upper rectilinear portion 54.

When the belt wheel 40 is rotated in the counterclock wise direction asviewed in FIG. 4 any cross section of the carrier device 44 travels inthe direction of the arrow 54, 54, 54" and 54" in the manner as abovedescribed. Therefore, within the carrier device 44 as traveling alongthe upper rectilinear portion 54 of the close loop, a rectilinear streamof the abrasive having the effective length of L is formed in thatportion 54. This stream is utilized to surface finish workpieces in thesame manner as previously described in conjunction with FIGS. 1 to 3inclusive. Thus workpieces 56 successively pass from their startposition 56 to a working line 68 along which they are surface finishedand then delivered to their finished position 56.

As an example, an apparatus such as illustrated in FIGS. 4 to 8 was usedto surface finish pin-shaped workpieces. and screws. While the pointedends of the pinshaped workpieces or the heads of the screws weremaintained projecting from the surface of the rectilinear stream portionof the loose abrasives they were successively passed through that streamportion at a relative speed as above specified for a period of time asabove specified. During movement they were tilted at any desired angleto the direction of the stream and/ or they were rotating about theiraxes. In this way their particular portions could be successfullysurface finished.

Referring now to FIGS. 9 to 13 inclusive, there is illustrated anothermodification of the invention especially suitable for surface finishinglong large-sized workpieces. Two pairs of chain wheels 110, a, 112 and112:: having the horizontal shafts (not shown) are suitably supported ona machine frame (not shown) such that a line passing through the centersof the wheels 110 and 112 of one wheel pair crosses a line passingthrough the centers of the Wheels 110a and 112a of the other pair toform an X-shaped arrangement. A pair of carrier devices 114 and 114a ofchannelled endless belt type as will be hereinafter described aretightly spanned between the wheels 110 and 112 and between the wheels110a and 112a respectively with endless chains and endless beltsinterposed therebetween. Thus both carrier devices are juxtaposed in anX-shaped arrangement. Only the chains and belt for device 114 are shownby the reference numerals 116 and 118 respectively. The lower wheels 110and 110a are adapted to be driven in the opposite directions by a commonelectric motor through a suitable transmission mechanism to rotate bothcarrier devices 114 and 114a in the corresponding directions and in therespective vertical planes although the motor and transmission mechanismare not shown for purpose of simplification. If desired, the upperwheels 112 and 112a may be similarly driven by the same motor. With thearrangement illustrated, any cross section of each device 114 or 114atravels along a rectilinear path between the associated pair of wheelsas in the previous arrangement.

The carrier devices 114 and 114a are of the same construction andtherefore one of the devices will now be described. As best shown inFIGS. 11 and 12, the carrier device 114 has a bottom composed of theendless belt 118 rigidly secured to the endless chain pair 16 engagingthe chain wheels 110 and 112 and both side walls each composed of aplurality of outwardly flared plates 120 alternating the similar plate121 with the plates 120 and 121 being attached to the chain 116 or thebelt 118 as shown in FIG. 12. These plates 120 and 121 overlap eachother when the associated portion of the carrier device 114 is movingalong the rectilinear path. When the plates are passing around eachchain wheel they will decrease in the overlapped area but still form thecontinuous side wall free from any gap therebetween. Therefore aquantity of abrasives loaded in the carrier device 114 as will bedescribed later is prevented from falling down from the side wall of thedevice during its movement.

As best shown in FIG. 10, a transfer chute 122 or 122a extends fromadjacent the upper chain wheel 110 or 110a for one of the carrierdevices 114 or 114a to that portion of the other carrier devicepositioned directly below the top of the one carrier device to permitthe abrasives to transfer from one to the other of the carrier devices.

In order to initially load a quantity of abrasives into each of thecarrier devices 114 or 114a, both devices may be first driven in themanner as previously described.

Then a quantity of abrasives is fed into each of the moving carrierdevices 114 or 114a from the lower end of its upper rectilinear sectionformed between the associated upper and lower wheels or the associatedchute 122 or 122a to form a layer 124 or 124a of abrasives loosely anduniformly distributed to a predetermined depth in the upper rectilinearcarrier section throughout the length whereupon feeding of the abrasiveterminates. It is to be noted that each of the carrier devices should beinclined at such an angle that the layer of abrasives 124 or 124a doesnot collapse within the ascending rectilinear carrier section. As soonas any portion of the abrasive layer 124 has reached the upper end ofthe ascending rectilinear carrier 114 section it falls down onto theother rectilinear section through the associated chute 122. Then thefalling portion of the abrasives in the form of a layer ascends in therectilinear section as the latter moves upwardly. When any portion ofthe abrasive layer 124a has reached the top of the latter section, itfalls down onto the original rectilinear carrier section through thechute 122a to repeat the process just described. Thus it is apparentthat the layers of abrasives 124 and 124a travel along a closed loopincluding a pair of rectilinear portion inclined and crossing eachother. Namely there have been established a pair of rectilinear streamof the abrasives crossing each other into an X-shaped arrangement.

Under these circumstances, holding and driving means of any knownconstruction can be used to surface finish workpieces one after anotherwith either or both of the two rectilinear abrasive streams in thesimilar manner as previously described in conjunction with FIGS. 1 to 3inclusive. For example, one of workpieces 126 is fed in the direction ofthe arrow 128 from adjacent the upper end of the rectilinear carriersection into the carrier device 114 through the use of holding anddriving means schematically designated at a rod connected to theworkpiece 126. In the carrier device 114 it descends along therectilinear carrier section in counterfiow relationship while beingsurface finished with the abrasives in the rectilinear abrasive stream.Near its position just below the upper Wheel 112 the workpiece is movedfrom the carrier device 114 to its position 126" as shOWn in thedot-and-dash arrow 128. Thereafter the workpiece is moved in the othercarrier device 114a as shown at the dot-and-dash arrow 128" and 128'(see FIG. with its orientation remaining unchanged. Then the workpiecesuch as 126 is subject to surface finishing in the carrier device 114ain the same manner as in the device 114 after which the workpiece ispassed from the device 114a to its position 126". In this way theworkpiece has been completely surface finished. The process justdescribed is repeated with the succeeding workpieces.

Altemately the surface finishing operation may be started with thecarrier device 114a with the workpieces transferred from the device 114ato the devices 114 at the lefthand side thereof as shown at thedot-and-dash arrow 128" (see FIG. 10).

In FIGS. 9 and 10 the stream of abrasives are designated at the arrows120, 120, 120 and 130, 130, 130" etc. and the workpieces being surfacefinished are illustrated at various positions 126', 126" etc.

From the foregoing it will be appreciated that according to the surfacefinishing operation as above described, the workpieces are surfacefinished in the opposite directions resulting in no occurrence ofpartial polishing and polishing shadows due to the conventionalundirectionally surface finishing methods and hence in uniform and homogeneous finishing. This is particularly effective for surface finishinglong workpieces such as mufflers for use in autobicycles, bumpers,radiator grilles and decorative straps for use in automobiles and thelike. It will be also understood that the workpieces within one ofcarrier devices 114 or 114a are automatically maintained at an angle ofinclination corresponding to that of the latter and that the workpiecestransferred from the device 114 to the device 114a and vice versa havean angle of inclination automatically varied so as to correspond that ofthe device 114a or 114 by the action of resistance to the workpieces ofthe rectilinear abrasive stream.

Alternatively both carrier devices 114 and 114a may be put in separateworking lines beginning at the position 126 and 126 and terminating atthe position 126" and 126".

If desired, the chutes 122 and 122a each may be operatively coupled witha motor-operated vibrator (not shown) to aid in transferring theabrasives from one to the other of the carrier devices. Alternatively, arotary disk or rollers (not shown) may be disposed on the bottom of eachchute.

Dependent upon their configuration, the workpieces may effect, inaddition to rectilinear movement in the rectilinear abrasive stream,rotational movement about their axes and/or serpentine movement in thevertical and/ or horizontal directions or direction.

Conveniently cover means (not shown) may be pro vided for covering eachof the carrier devices 114 or 114a to prevent the abrasives fromscattering from the associated device.

With the wet type of abrasives used a liquid such as water containing asuitable compound or compounds may be poured into the layer of abrasives124 or 124a at the upper end of the associated rectilinear carriersection and exhausted from the lower end of each chute (not shown).

If desired, the endless chain pair may be omitted and instead of theendless belt may directly engage belt wheels used in place of the chainwheels as shown in FIG. 13 wherein like reference numerals designate thecomponents similar or corresponding to those illustrated in FIG. 12.

The figure of the speed and dimension of the rectilinear abrasivestream, the speed of the workpiece relative to the latter and thefinishing time referred to the arrangement shown in FIGS. 1 to 3inclusive are equally applicable to the arrangement illustrated in FIGS.4 to 8 or FIGS. 9 to 13 inclusive.

Unlike the conventional type of gyration finishing methods in which acylindrical barrel having loosely loaded therein a quantity of abrasivesis rotated to form a flowing layer of the abrasives in the form of adisk, a cone, or a cylinder, and wherein workpieces are forced on or putinto the flowing layer to be finished, the invention is characterized inthat a rectilinear stream of abrasives is used resulting in thepossibility of easily subjecting workpieces to uniform surface finishingfree from partial polishing and/ or polishing shadows due to theconventional finishing methods.

While the invention has been illustrated and described in conjunction tothe several preferred embodiment thereof, it is to be understood thatvarious changes and modifications may be resorted to without departingfrom the spirit and scope of the invention. For example, the arrangementshown in FIGS. 1 to 3 and FIGS. 4 to 8 inclusive may be rotated in theclockwise direction rather than counterclockwise direction with theworkpieces moved in a direction reversed from that described.

What I claim is:

1. In an apparatus for surface finishing workpieces, the combination ofmovable carrier means of channelled endless belt type of a flexibledurable material, a pair of driving belt wheel and a tuning belt wheelfor spanning said carrier means in tensioned state to form a pair ofparallel rectilinear sections therebetween, a quantity of abrasivesloosely and uniformly distributed in the form of a layer within saidcarrier means, means for maintaining a substantially U-shaped crosssection of at least one of said rectilinear sections of said carriermeans, and means for holding and driving the workpieces one afteranother to move, at a predetermined relative speed, the workpieces incounterfiow relationship with respect to a rectilinear stream portion ofsaid abrasive layer in said U-shaped rectilinear section of said carriermeans driven by said driving belt wheel While maintaining the workpiecesin surface finishing engagement with said rectilinear stream (bee-lineflow) portion.

2. An apparatus for surface finishing workpieces as claimed in claim 1,wherein said carrier means are rotatably disposed in horizontal planeand wherein said carrier means are maintained in a substantially U-shapeof cross section and guided by both a plurality of bearing rollersdisposed on the bottom and a plurality of side guide rollers disposed oneach side wall with at least one of the U-shaped rectilinear sections ofthe carrier device utilized for surface finishing the workpieces.

3. An apparatus for surface finishing workpieces as claimed in claim 1wherein said carrier means have a pair of opposed side wallslongitudinally undulating with valleys of the undulation disposed atsubstantially equal intervals and inwardly foldable and are rotatablydisposed in a vertical plane and wherein said carrier means have anupper rectilinear section maintained in a substantially U-shape of crosssection and guided by both a plurality of bearing rollers disposed onthe bottom of the section and a plurality of side guide rollers disposedon each side wall while having the remaining section maintained andguided in its closed state by a plurality of rollers disposed on each ofthe four sides of the sections.

4. In an apparatus for surface finishing workpieces comprising thecombination of a pair of carrier means of U-shaped endless belt typejuxtaposed in tensioned state in the vertical planes by having two pairsof belt wheels engaging the same respectively, both said carrier meansbeing rotatable in the opposite directions with the upper rectilinearsections thereof ascending, a layer of abrasives loosely and uniformlydisposed in each of said upper rectilinear carrier sections, chute meansextending from adjacent the upper end of each of said rectilinearcarrier section to that portion of the other rectilinear carrier sectionpositioned below said upper end of said each rectilinear carriersection, and means for holding and driving the workpieces one afteranother to move, at a predetermined relative speed, the latter incounterflow relationship in said ascending layer of abrasives whilemaintaining the workpieces in surface-finishing engagement with saidlayer of abrasives. v

5. An apparatus for surface finishing workpieces'as claimed in claim 4,wherein each of said carrier means has both side walls each composed ofa plurality of outwardly flared plates alternating the similar plates.

6. An apparatus for surface finishing workpieces as claimed in claim 4,wherein saidpredetermined relative speed ran es from to 500 meters perminute.

References Cited UNITED STATES PATENTS JAMES L. JONES, 111., PrimaryExaminer

